In prior art, the light-reflecting sheet or plate is mainly used for reflection and refraction of light rays. Later strip-type micro prisms are added for better reflection and refraction of the sun light and further, lighting fixtures are added at both ends to function as both luminous panel and lighting. In Chinese patent No. 200510029375.1, the applicant invented a micro prism-type sunlight reflecting plate and its regulating device, wherein the surface of the light-reflecting plate is equipped with several parallel micro prism bodies having the shape of isosceles right triangles, the vertex angle of which is 90° and the base angle is 45°. On each end face, there is blind hole to receive the LED lamp bodies. This kind of light-reflecting plate is used for rooms with glass ceiling, windows or skylights, which gives sufficient access to sunlight in winter and completely or partially reflects back the sunlight in summer. It shades from direct sunlight while ensuring adequate lamination indoors. The lamp bodies on both ends can provide additional lighting at dark weather or at night. Although the light-reflecting plate of this structure can make the overall plate to function as a luminous surface under the action of the lamp bodies, its luminance is very low due to limitation by design structure.
Inspired after the aforesaid patent, the applicant envisages how to employ the combination of light-reflecting plate and LED with lighting fixtures and starts to study on changing the point light source of the light-reflecting plate to surface light source via LED. That is to use LED for lighting other than for decoration. For this purpose, the applicant has disclosed two light-reflecting plates in PCT/CN2007/002052 and PCT/CN2008/000031. Among them, one is flat light-reflecting plate, wherein one surface is arranged with several parallel strip-type micro prism bodies, the cross sections of the left and right scalene right-angle triangles adjacent to the symmetrical central plane are the largest and the cross sections towards the left and right sides are successively decreasing. The other is a circular light-reflecting plate consisting of right-angle triangular micro prisms with the central axis as the symmetrical center, wherein several annular micro prism bodies are formed in its radial direction with its cross section and section area being the same with those of the flat one. After blind holes and lamp bodies are equipped on both ends and circumferential faces of the two light-reflecting plates, for example, circular light-reflecting plate has lamp bodies which are arranged thereon, and the emission centers of these lamp bodies are parallel to the plane of the light-reflecting plate, or pass through the apexes of the inclusion angles of the annular prism bodies on the plane of the light-reflecting plate. The light emitted from the lamp bodies will reflect from the micro prism bodies, resulting in good lighting effect.
In further studies, it has been found that the flat and circular light-reflecting plates with the above-mentioned structures show the shortcomings that the reflecting and emitting light rays on one plane from the light-reflecting plate via the prisms are non-uniform (influencing the lighting effect) and small scale of light sheets made of light-reflecting plate, that is, asymmetrical one-side micro prism layout. The above both patent applications have not addressed these problems.